Small electronic components, including amplifiers, filters, transducers and the like, are employed in a number of devices, particularly in radio frequency (RF) wireless communications, for example. Various types of filters, for example, include acoustic filters, such as surface acoustic wave (SAW) resonator devices containing SAW resonators, and bulk acoustic wave (BAW) resonator devices containing thin film bulk acoustic resonators (FBARs) and solidly mounted resonators (SMRs), for example.
Conventionally, the electronic components are combined in circuit packages and covered with external shields to form discrete shielded packages, referred to as “modules.” The external shields are generally shield layers that cover the top and side walls (coating five sides) of the circuit packages, and provide protection against externally generated electromagnetic radiation (“external electromagnetic radiation”), as well as and environmental stresses, such as temperature, humidity, and physical impact, for example (e.g., hermetic sealing). In order to provide protection against the external electromagnetic radiation, the external shields are formed of either electrically conductive material, typically metal or alloy, or a combination of electrically conductive and non-conductive material. The bottoms of the circuit packages are typically not shielded by the external shield layers, although the substrate itself, external connecting pins protruding from the substrate and/or various electronic components, transmission lines and other circuitry within the substrate generally may provide some external shielding from external electromagnetic radiation. The external shield layers together with the bottom shielding together provide a “global shield” for the module.
However, coating the top and side walls of the circuit package is costly, time consuming and overall inefficient, since applying the conductive material can be done only after singulation of the individual circuit packages. That is, electronic components of multiple circuit packages are formed in or on a single substrate (or wafer) and covered with a molded compound to provide corresponding multiple circuit packages. The single substrate is then separated (e.g., by sawing or laser ablation) into the separate circuit packages, each of which must then be individually coated by the conductive material on the top and side walls for external electromagnetic radiation shielding.
Accordingly, there is a need for a fabrication process, and a resulting shielded package or module that enables application of external electromagnetic radiation shielding prior to singulation of the circuit packages into individual modules, thus avoiding the step of having to individually coat the circuit packages with conductive material after separation.